Pneumatic pump



April 1970 A. E. SCHMIDLIN PNEUMATIC PUMP Filed July 5, 1968 INVENTOR ALBERTUS E. SCHMIDLIN a KW ATTORNEY United States Patent 3,508,848 PNEUMATIC PUMP Albertus E. Schmidlin, Caldwell, N.J., assignor to Singer General Precision, Inc., a corporation of Delaware Filed July 5, 1968, Ser. No. 742,558 Int. Cl. F04b 17/00 US. Cl. 417395 11 Claims ABSTRACT OF THE DISCLOSURE A pneumatic pump having a hollow housing divided into a resonant cavity and a pumping chamber by a diaphragm. Means are provided to produce pressure waves in the cavity to pump liquid through the chamber.

BACKGROUND OF THE INVENTION This invention relates to a pump and, more particularly, to such a pump which receives its motive power from the output of a pneumatic oscillator.

Certain essential portion of the present disclosure are hereby incorporated herein by reference to US. Patent No. 3,419,028 entitled Fluid Oscillator, issued jointly on Dec. 31, 1968 to A. E. Schmidlin and C. W. Bing, and assigned to the assignee of the present invention.

It is generally known to provide a flexible diaphragm, or the like, to pump fluid through a chamber. However, in these arrangements, the driving or motive force behind the pumping action requires the use of mechanical means which, of course, is subject to wear and breakdown, in addition to being sensitive to nuclear radiation, extreme temperatures, shock, etc.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a pump which is actuated by a pneumatic oscillator, which has a minimum of moving parts, and which is not affected by hostile environments.

Briefly summarized, the pump of the present invention comprises a pneumatic oscillator which utilizes the pressure waves formed in a resonant cavity to develop cyclic forces on a flexible diaphragm, the movement of the latter, in turn, being utilized to pump a constant head of fluid.

BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying drawings for a better understanding of the nature and objects of the pump of the present invention, which drawings illustrate the best mode presently contemplated for carrying out the objects of the invention and its principles, and are not to be construed as restrictions or limitations on its scope. In the drawings:

FIG. 1 is a horizontal cross-sectional view of the pneumatic pump of the present invention;

FIG. 2 is a cross-sectional view taken along line 22 of FIG. 1; and

FIG. 3 is a view similar to FIG. 2, but showing an alternate embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring specifically to FIGS. 1 and 2, which show the pump of the present invention, the reference numeral refers in general to a cylindrical housing formed by a cylindrical upper housing member 12 having flanges extending from its outer periphery in contact with a cylindrical lower housing member 14. An inlet tube 16 and an outlet tube 18 extend through the upper housing member 12 and register with the space formed by the housing members.

A flexible member 20, such as a diaphragm, has its outer portion clamped between the upper and lower housing members 12 and 14 to divide the space between the housing members into a resonant cavity 15 and a pumping chamber 17. The latter chamber, in turn, is divided into chambers 17a and 17b by a diametrical partition 19.

It is understood that the particular design of the resonant cavity 15 defined by the upper housing member and a diaphragm can be made in accordance with the principles fully disclosed in the aforementioned Patent No. 3,419,028. Thus, for example, inlet tube 16 may correspond to inlet 28 of FIGURE 1 in the patent, while outlet tube 18 may comprise the equivalent of the outlet tube 42 in the same FIGURE 1 embodiment.

A pair of inlet valves shown generally at 22 and 24 are provided in the lower housing member 14, and each consists of an inlet passage 26 communicating with a cylindrical chamber 28 which, in turn, registers with a tangential angular passage 30 in communication with the chambers 17a and 17 b. As will be explained in greater detail later, this arrangement forms a fluidic diode of the vortex type.

A pair of outlet valves 32 and 34 are provided in the lower housing member 14 and are disposed radially inwardly from the inlet valves 22 and 24. These outlet valves are similar to the inlet valves 22 and 24 and each comprises a passage 40 which connects the chambers 17a and 17b with a cylindrical chamber 38 which, in turn, communicates with a passage 36.

In operation, a driving gas, such as nitrogen, is passed into the cavity 15 through the inlet tube 16 in the direction shown by the arrow A. This gas, under a substantially constant head, assumes a particular flow pattern in the cavity 15 and empties through the outlet tube 18 in the direction shown by arrow B. The design is such that the gas is made to oscillate with an increased amplitude at a particular resonant frequency to produce pressure waves across the cavity which develop cyclic forces on the diaphragm 20, resulting in a highly amplified digital type oscillatory movement of the latter in a vertical direction with reference to FIG. 2. This latter motion, in turn, induces a flow of the fluid to be pumped through the inlet valves 22 and 24 in the direction shown by the arrow C, and imparts an action to the fluid in the chambers 17a and 17b to pump it outwardly through the outlet valves 32 and 34 in the direction shown by the arrows D. Of course, if the suction, or upward stroke of the diaphragm alone is not enough to eifect flow of the fluid through the inlet valves, external means may be used, such as means to pressurize the fluid.

It is understood that, since the amplitude of each pressure wave generated in the cavity 15 varies at different points in the cavity, the inlet and outlet valves are positioned at points which are optimum for pumping purposes.

The particular arrangement of the inlet and outlet valves is such that only one-way flow is effected through each. In particular, the inlet valves 22 and 24 are designed so that fluid entering the passage 26 of the valve 22, for example, will readily flow through the chamber 28 and the tangential passage 30 into cavity 15. However, upon action of the membrane 20 in the opposite direction to this flow, the fluid will pass from the passage 30 into the chamber 28 in a direction substantially tangential to the latter, which will cause the fluid to form a vortex in chamber 28, thereby substantially preventing further flow from the latter in this opposite direction. Therefore, in effect, a fluidic diode, or one-way valve, is formed. These same principles apply in connection with the outlet valves 32 and 34, with the exception, of course, that fluid flow is prevented in an opposite direction.

The embodiment of FIG. 3 is substantially similar to that of FIGS. 1 and 2 but utilizes a diflferent oscillating action to drive the diaphragm. In particular, a cylindrical housing 50 is shown which comprises an upper housing member 52 and a lower housing member 54. As in the previous embodiment, a diaphragm 58 is disposed between the housing members and defines a resonant cavity 56 and a pumping chamber 57.

A conical shaped aperture 60 is formed in the upper housing member 52 and receives an inlet tube 62, one end of which is tapered to define an annular outlet passage 66. The inner surface of the lower housing member 54 is shaped to form a crest portion 70 over which the diaphragm 58 extends. A tube 76 is provided on the lower housing member 54 with its bore extending through the crest portion 70 in alignment with the bore of the inlet tube 62.

As in the previous embodiment, a pair of inlet valves 78 and 80 are provided in the lower housing member 54 along with a pair of outlet valves 82 and 84, it being understood that these valves are in the form of fluidic diodes, as described above.

The membrane 58 is driven by supplying a gas, such as nitrogen, through the bore of the inlet tube 62 in the direction indicated by the arrow A whereupon it flows radially outwardly in the cavity 56 with a portion thereof flowing to and from the tube 76, as shown. The radially extending pressure waves drive the membrane 56 causing it to oscillate in a vertical direction and the driving gas exits through the outlet passage 66 in the direction of the arrows B.

The oscillatory motion imparted to the diaphragm 58 is utilized in the same manner as in the previous embodiment to pump a fluid entering through the inlet valves 78 and 80 into the chamber 57, outwardly through the outlet valves 82 and 84.

It is thus seen that the pumps of the present invention utilize no moving parts with the exception of the diaphragms and, therefore, are low in cost, reliable, and suitable for a long life. Also, the pumps of the present invention are not influenced by hostile environments such as nuclear radiations, extreme temperatures, shock, etc.

Of course, other variations of the specific construction and arrangement of the pumps disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.

What is claimed is:

1. A pneumatic pump comprising a hollow housing, a flexible member disposed in said housing and dividing the hollow portion thereof into a resonant cavity and a pumping chamber, said chamber having at least one inlet means and one outlet means for pumping fluid therethrough, and means for passing a driving fluid through said resonant cavity wherein said driving fluid is caused to produce resonant pressure Waves of increased amplitude and to thereby develop cyclic forces on said flexible member to pump said first mentioned fluid through said outlet means.

2. The pump of claim 1 wherein said cavity is cylindrically shaped and wherein said driving fluid is passed radially across said cavity.

3. The pump of claim 1 wherein said cavity is cylindrically shaped and wherein said driving fluid is passed from a central portion of said cavity radially outward.

4. The pump of claim 1 wherein said inlet means and said outlet means include fluidic diodes.

5. The pump of claim 1 wherein said inlet means and said outlet means are in the form of two inlet passages and two outlet passages, the inlet passages being disposed radially outward from the outlet passages.

6. The pump of claim 5 wherein each of said passages is shaped to form fluidic diodes.

7. The pump of claim 1 wherein said cyclic forces on said diaphragm also induce the flow of fluid through said inlet means.

8. The pump of claim 2 wherein said means for passing a driving fluid through said resonant cavity comprises an inlet port coupled to the cylindrical wall of said housing and an outlet port coupled to one end wall of said housing coaxial with the housings central axis, said outlet port being orthogonally aligned relative to said inlet port.

9. The pump of claim 8 wherein said driving fluid inlet port comprises an inlet noule for admitting driving fluid under a constant pressure head to said resonant cavity at a supersonic entrance velocity.

10. The pump of claim 3 wherein said means for passing a driving fluid radially outward from a central portion of said resonant cavity comprises an aperature centrally disposed in one end wall of said cylindrical housing for communicating with said cavity, and an inlet nozzle coaxially supported within said aperture for supplying said driving fluid to said cavity, said aperture defining an annular clearance space around said nozzle for exhausting said driving fluid from said cavity.

11. The pump of claim 10 wherein said other end wall of said cylindrical housing comprises a centrally disposed crest portion in spaced relation to said inlet nozzle and coaxial with respect thereto, said crest portion providing a central support for said diaphragm and including a tubular depression for tuning the resonant frequency of said cavity.

References Cited UNITED STATES PATENTS 3,016,840 l/1962 Frick 10344 3,039,309 6/1962 Vesper et al lO3-44 XR 3,323,550 6/1967 Lee l378l.5 XR

ROBERT M. WALKER, Primary Examiner US. Cl. X.R. 137-815 

